Power-operated slicing knife



Oct. 13, 1964 A. FREEMAN 3,152,398

POWER-OPERATED SLICING KNIFE Filed July 29, 1965 40 V f/7V6/7 far:

. 4/Mwr 6/ Fr: man 3/ 37 30b 26 AIM/fig United States Patent 3,152,398 POWER-OPERATED SLlClNG KNEE Arthur H. Freeman, Brockport, N.Y., assignor to General Electric Company, a corporation of New York Filed July 29, 1963, Ser. No. 298,305 Claims. ((11. 39272) This invention relates to a power-operated slicing knife and in particular to a drive mechanism for such a knife.

In the field of hand-held slicing knives, knives having a cutting blade which is reciprocated by a power-operated drive mechanism have been found to achieve a desirable cutting action. The drive mechanism of such knives may be mounted on a support or handle which is held by the users hand during operation to permit manual manipulation of the knife blade.

In such hand-held slicing knives the drive mechanism is preferably lightweight as well as capable of withstanding repeated stresses in providing reciprocating knife blade action. Furthermore, where the knife is intended for domestic culinary cutting chores it is desirable that the drive mechanism be free from irritatingly loud operating noise and from high vibration which interferes with cutting accuracy and safety.

Size is another factor of importance in the design of a drive mechanism for hand-held knives to enable convenient hand manipulation by the user. Where the poweroperated knife uses a pair of oppositely reciprocating knife blades, particular attention must be paid to size, due to the need for drive means for two blades. My present invention is an improvement on the invention disclosed and claimed in the application of Thomas F. Nelson, Serial No. 298,301, filed July 29, 1963 and assigned to the assignee of the present application, which invention was made by Thomas F. Nelson prior to my invention.

Accordingly, it is one object of this invention to provide a drive mechanism for a power-operated slicing knife which imparts a reciprocating motion to the knife cutting means and has minimum wear and noise characteristics, high durability and ease of assembly.

It is yet another object of this invention to provide in a hand-held power-operated slicing knife having a pair of counter-reciprocating blades, an improved drive mechanism of minimum size.

In carrying out the objects of my invention in one form thereof, a power-operated slicing knife, having drive means and a pair of reciprocating blades, is provided with rotary driven means to operate the blades from the drive means with a rapidly reciprocatnig motion. The driven means includes a crank assembly connected to the drive means and having a pair of eccentrically mounted followers. A pair of connecting rods are provided, each having a portion in which a follower is received to drive each connecting rod with a reciprocating motion. Each follower is pivotal on the crank assembly and provides at least two fiat peripheral surfaces which are slidable between corresponding surfaces in its connecting rod. Each knife blade is engageable with a connecting rod to be driven thereby.

Other objects and advantages of my invention may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of a power-operated slicing knife having a portion of its housing cut away to reveal certain elements of the drive unit;

FIG. 2 is a plan view of the drive mechanism of the knife of FIG. 1 with a portion of the housing removed and certain elements cut away for clarity;

FIG. 3 is a perspective view of the crank assembly of the drive unit showing one connecting rod engaging the crank assembly and one crank support bearing;

FIG. 4 is an end view in cross section of the crank assembly of FIG. 3 and the motor drive shaft; and

FIG. 5 is a side view of the crank assembly of FIG. 3.

A preferred form of my invention is shown in FIG. 1 having a handle or housing 10 and a pair of knife blades 11 and 12 extending longitudinally from the forward end of the housing. The knife blades are held in close contact along their inner surfaces by any conventional means such as a keyhole slot and rivet arrangement 13.

Enclosed within housing 10 is a drive mechanism including an electrical motor 14, a crank assembly or transmission 15, a pair of connecting rods 16 and 17, and a pair of blade receiving members or channels 18 and 19. Motor 14 is adapted for connection to a suitable power source such as a household alternating current outlet. The rearward portions of blades 11 and 12 are accommodated in channels 18 and 19 respectively and adapted for connection to the forward portions of connecting rods. Connecting rods 16 and 17 are secured to channels 18 and 19 by fasteners such as 19:: and extend forwardly to the forward end of housing 10. A bearing support or seat 20 is secured to the lower portion of housing 10 having a retainer or cover 21 secured thereto by fasteners 22.

Bearing seat 20 and retainer 21 have been partially cut away in FIG. 1 to show one of a pair of hardened wear strips such as 23 which are clamped downwardly against the lower internal surface of housing 20 by the forward end of the bearing seat. Wear strips 23 extend rearwardly to overlie integral horizontal flanges (not shown) formed on the lower portion of bearing seat 20. The lower surfaces such as 17a of the rearward or yoke portions of the connecting rods are slidingly supported on strips 23. As may be seen more clearly in FIG. 2, bearing seat 20 also provides support for forward bearing 24 of motor shaft 25 as well as for crank assembly journal bearings 26 and 27. The forward end of motor shaft 25 includes a Worm drive 28 which meshes with a helical worm gear 29 of crank assembly 15.

The unique crank assembly of my invention shown in detail in FIGS. 3-5, includes in addition to gear 29, a pair of pivots or pins 30 and 31, a pair of followers 32 and 33, and a pair of journals 34 and 35. Gear 29 includes a hub 36 and preferably consists of phenolic resin having a laminated linen base. This construction has shown high wear resistance.

Pins 30 and 31 are generally cylindrical and have portions of their cylindrical surfaces splined for engagement with hub 36 of gear 29 and the crank assembly journal. The inner surfaces 30a and 31a of the pins are press fitted into bores 37 and 38 formed in hub 36. The axes 37a and 38a of the hub bores are parallel to and spaced equidistantly from axis 36a of the hub and diametrically opposed to one another on opposite sides of the hub axis, i.e., they are positioned apart. The outer surfaces 30b and 31b of the pins are press fitted into bores 39 and 40 formed in journals 34 and 35 respectively.

Journals 34 and 35 are secured to hub 36 so as to be concentric therewith for rotation about am's 36a. Crank assembly 15 is mounted within housing ltl by means of journals 34 and 35 which are supported in bearings 26 and 27, the latter being shown most clearly in FIG. 3.

In accordance with my invention, followers 32 and 33 are pivotally mounted on central bearing portions of pins 34) and 31 respectively. To provide a maximum area for driving contact between the followers and the rearward or yoke portions lb and 17b of the connecting rods 16 and 17, the followers include fiat peripheral surfaces such as 33a and 33b shown in FIG. 5. Preferably the followers are generally square so as to provide two pairs of flat parallel surfaces of equal size. The follower corners are chamfered to assist in assembling the followers to the connecting rod yokes lb and 17b. Furthermore, the followers are made of oil impregnated sintered iron to increase Wear characteristics and provide self lubrication.

The yoke portions ofthe connecting rods are provided with vertical surfaces such as 170 and 17d which are spaced from one another a distance slightly greater than the width of the followers. These flat vertical surfaces guide and confine the followers to a vertical path relative to the connecting rods during operation of the crank assembly.

The operation of the drive mechanism of the slicing knife is as follows. When motor 14 is operated so as to rotate shaft 25, worm 28 on shaft 25 drives worm gear 29. This action converts the rotation of the motor about an axis parallel to the axis of the housing (and the axis of the knife blades) to rotation of the crank assembly 15 about an axis transverse to the housing and knife blade axis. Crank assembly 15 then operates to convert this rotary motion of gear 29 to reciprocating motion of connecting rods 16 and 17.

Gear 29 and journals 34 and 35 of the crank assembly rotate in placeabout the fixed axis of the journals as determined by bearings 26 and 27 and bearing seat retainer 21. At the same time, pins 30 and 31 being fixed to gear 29 describe circular paths about axis 36. As followers 32 and 33 are pivotal on the central bearing portions of the pins, and are confined front and rear between the vertical surfaces, such as 17c and 17d, ofthe connecting rod yokes, the followers drive the connecting rods with a reciprocating motion as the crank assembly turns. Any rotative or vertical motion of the connecting rods is prevented by means of a guide 41 (see FIG. 1) which confines the forward portions of channels 13 and 19 for sliding movement therein; the rearward or yoke portions of the connecting rods are vertically confined between wear strips 23 and the lower surface of the horizontal top portion 42 of bearing seat retainer 21. While the crank assembly rotates, the followers pivot about their respective pins and slide up and down between the vertical surfaces of the connecting rod yokes.

It can be seen that connecting rods 1d and 17 are driven a distance equal to the longitudinal movement of the contacting follower surfaces as the followers move from their neutral top and bottom positions to their extreme forward and rearward positions. In other words, the

stroke length of the connecting rods is determined by the eccentric distance between the axis 36a and the hub bore or pin axes 37a and 3&1. A satisfactory stroke length of 7 inch has been achieved with an eccentric distance of inch. Of course the stroke length of the connecting rods is substantially synonymous with the stroke length of the knife blades, as each connecting roddrives its respective channel and knife blade as a unit.

The crank assembly of this invention has been found to be free from excessive wear when the motor and gear 29 are designed to rotate the crank assembly at 2,000 revolution per minute. This slicing rate coupled with the 7 inch stroke results in excellent slicing action.

It is an important concept of my invention that the flat forward and rearward surfaces such as 33a and 33b of the followers drive the connecting rods with short rapid reciprocating strokes. Due to the high acceleration and deceleration forces to which the follower is subjected during the rotation of the crank assembly, high impact forces are created between the followers and the connecting rod yokes. The unique flat-surface contact between the follower and the yoke maximize the area of impact forces to reduce the wear which would be experienced with other followers such as round or elliptical followers having a line contact. The line contact type followers have been found to result in excessive wear at their line of contact with the connecting rod yoke at the points of maximum acceleration. Such wear is particularly undesirable in that the play or looseness between the fol- A lower and the yoke, resulting from the initial wear, rapidly multiplies due to the mismatched velocities of the follower and the yoke.

Of course, as wear is reduced, the noise of the drive mechanism is also reduced in that a portion of such noise results from the looseness between the follower and the yoke.' For the same reason, the vibration of the knife is reduced by the use of the flat-sided followers; it should also be noted that the diametrically opposed followers are traveling simultaneously, with the connecting rods and the knife blades, in opposite directions so as to balance out many of the shock forces during operation.

The generally square configuration has been found to be preferable for use during assembly of the knife drive unit in that the follower may be slid downwardly into the yoke of the connecting rod with any 'two opposite flat faces engaging the flat vertical yoke surfaces. Should wear take place between a pair of opposite follower surfaces, the square configuration permits later use of the remaining pair of opposite flat drive surfaces. The chamfering of the follower corners, like the open top construction of the yoke portion of the connecting rods, also assists in simplifying assembly of the crank assembly 15 in the drive mechanism of the knife.

I have thus described a drive mechanism for a poweroperated slicing knife which is capable of rapid reciproca tion of one or more knife blades with a minimum of noise, wear and vibration. Furthermore, the compact unitary construction of the crank assembly is designed to consume a minimum of space within the knife housing and to greatly simplify the assembly of the drive mechamsm.

The close side by side mounting of the worm gear; the followers and the journals provides a crank assembly for a pair of knife blades which eliminates any wasted space within the drive housing. The minimal width of the crank assembly is evident in FIG. 4.

While I have thus shown and described a specific embodiment of my invention, I do not desire my invention to be limited to the particular construction shown and described. Instead, I intend by the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim is:

1. A power-operated slicing knife comprising:

(a) a knife handle;

(b) an electrical motor in said handle adapted to be connected to a source of power;

(0) rotary driven. means within said handle in driving engagement with said motor for rotation about a given axis;

(d) a pair ofpins, one projecting laterally from each side of said driven means, said pins being parallel to said given axis and spaced therefrom in diametric opposition to one another;

(e) a journal secured to each of said pins for rotatably supporting said driven means in said handle;

(f) a pair of followers, each of said followers being rotatable on one of said pins and each having a pair of flat peripheral surfaces generally parallel to one another;

(g) a pair of connecting rods, each of said rods including a pair of generally parallel flat surfaces spaced from one another so as to receive one of said followers;

(It) said peripheral surfaces of each of said follower being in close contact with said parallel surfaces of one of said connecting rods so that rotation of said driven means operates said connecting rods with a counter-reciprocating motion; and

(i) a pair of knife blades, each adapted for connection to one of said connecting rods for reciprocation with said rods.

2. An electrically operated slicing knife comprising:

(a) a knife handle;

(b) an electrical motor in said handle adapted to be connected to a source of power and including a drive shaft having a given axis of rotation;

(c) gear means formed on said drive shaft;

(d) a crank assembly within said handle connected to said gear means including:

(aa) a driven gear in meshing engagement with said gear means having an axis of rotation transverse to said given axis,

(bb) means secured to said driven gear on opposite sides thereof for supporting said crank assembly in said housing,

(cc) a pair of laterally extending pivots connected to said driven gear and having axes parallel to said transverse axis and on opposite sides thereof, and

(dd) a pair of followers, each of said followers being rotatable on one of said pivots and including a pair of flat parallel peripheral surfaces;

(e) a pair of connecting rods mounted in said handle;

(7) means on each of said connecting rods including a pair of flat generally parallel surfaces spaced from one another to receive one of said followers;

(g) said peripheral surfaces of each of said followers being in driving contact with said surfaces of one of said connecting rods to drive said connecting rods with a reciprocating motion when said crank assembly is operated;

(11) means within said handle for slidingly supporting said connecting rods and for confining the motion of said connecting rods to reciprocation along an axis parallel to said given axis; and

(i) a pair of knife blades each adapted for connection to one of said connecting rods for reciprocation with said rods along an axis parallel to said given axis.

3. A power-operated knife comprising:

(a) an elongated hollow handle having a longitudinal axis;

([2) a pair of connecting rods;

(0) a pair of knife blades, each comprising:

(aa) a cutting portion extending forwardly from said handle parallel to said longitudinal axis; and

(bb) a rearward portion extending into said handle and adapted for engagement with one of said connecting rods;

(d) an electric motor mounted within said handle and adapted for connection to a source of power, said motor including an armature shaft having an axis parallel to said longitudinal axis;

(2) a crank assembly including:

(aa) a driven member in driving engagement with said motor shaft for rotation when said motor is energized;

(bb) means extending laterally on opposite sides of said driven member for supporting said assembly for rotation about an axis transverse to said handle axis;

(cc) a pair of pivots secured to said driven member, one of said pivots projecting from each side of said driven member and each having an axis transverse to said longitudinal axis;

(dd) a pair of generally square followers, each of 6 said followers being freely rotatable on one of said pivots and having a pair of flat peripheral surfaces generally parallel to one another;

(3) each of said connecting rods having a rearward yoke portion including a pair of generally flat parallel surfaces spaced from one another for receiving one of said followers for driving and sliding contact with said peripheral surfaces of said follower when said driven member is rotated; and

(g) means within said handle for slidingly supporting said connecting rods and for confining the motion of said connecting rods to reciprocation along an axis parallel to said longitudinal axis.

4. In a power-operated knife having a housing and a pair of knife blades, means for operating said blades with a reciprocating motion comprising:

(a) an electric motor including a drive shaft having gear means thereon;

(b) a rotary crank assembly within said housing having a given axis including:

(aa) a central gear means in meshing engagement with said gear means of said drive shaft;

(bb) a pair of pins, one of said pins projecting from each side of said gear parallel to and on opposite sides of said given axis;

(cc) a pair of journals, one positioned on the outer end of each of said pins for supporting said crank assembly within said housing; and

(dd) a pair of followers, each being mounted for free rotation on one of said pins between said gear and one of said journals and having a pair of generally parallel peripheral surfaces; and

(c) a pair of connecting rods, each of said connecting rods having a pair of generally parallel surfaces adapted to receive one of said followers therebetween so that said surfaces of said followers are in driving and sliding relation with said surfaces of said rods to drive said connecting rods with reciprocating motions along an axis transverse to said given axis when said motor is operated;

(d) said connecting rods being connected to the knife blades.

5. The power-operated knife recited in claim 3 wherein each of said followers includes four corners which are chamfered to facilitate assembly of said followers in said yoke portions of the connecting rods.

References Cited by the Examiner UNITED STATES PATENTS 1,417,094 5/22 Monroe 30-218 1,690,801 11/28 Van Bree 30-216 2,114,569 4/ 38 Paolini et al 30-272 2,155,708 4/39 Hartanov 30-220 X 2,168,703 8/39 Dziedzic et al. 30-173 2,278,174 3/42 Gray 30-220 X 2,380,787 7/45 Pierce et al. 30-220 2,623,283 12/52 Godfrey et al. 30-216 2,630,628 3/53 Hall 30-216 2,787,111 4/57 Templeton 74-50 X 3,014,276 12/61 Prohaska 30-272 WILLIAM FELDMAN, Primary Examiner.

MILTON S. MEHR, Examiner. 

1. A POWER-OPERATED SLICING KNIFE COMPRISING: (A) A KNIFE HANDLE; (B) AN ELECTRICAL MOTOR IN SAID HANDLE ADAPTED TO BE CONNECTED TO A SOURCE OF POWER; (C) ROTARY DRIVEN MEANS WITHIN SAID HANDLE IN DRIVING ENGAGEMENT WITH SAID MOTOR FOR ROTATION ABOUT A GIVEN AXIS; (D) A PAIR OF PINS, ONE PROJECTING LATERALLY FROM EACH SIDE OF SAID DRIVEN MEANS, SAID PINS BEING PARALLEL TO SAID GIVEN AXIS AND SPACED THEREFROM IN DIAMETRIC OPPOSITION TO ONE ANOTHER; (E) A JOURNAL SECURED TO EACH OF SAID PINS FOR ROTATABLY SUPPORTING SAID DRIVEN MEANS IN SAID HANDLE; (F) A PAIR OF FOLLOWERS, EACH OF SAID FOLLOWERS BEING ROTATABLE ON ONE OF SAID PINS AND EACH HAVING A PAIR OF FLAT PERIPHERAL SURFACES GENERALLY PARALLEL TO ONE ANOTHER; (G) A PAIR OF CONNECTING RODS, EACH OF SAID RODS INCLUDING A PAIR OF GENERALLY PARALLEL FLAT SURFACES SPACED FROM ONE ANOTHER SO AS TO RECEIVE ONE OF SAID FOLLOWERS; (H) SAID PERIPHERAL SURFACES OF EACH OF SAID FOLLOWERS BEING IN CLOSE CONTACT WITH SAID PARALLEL SURFACES OF ONE OF SAID CONNECTING RODS SO THAT ROTATION OF SAID DRIVEN MEANS OPERATES SAID CONNECTING RODS WITH A COUNTER-RECIPROCATING MOTION; AND (I) A PAIR OF KNIFE BLADES, EACH ADAPTED FOR CONNECTION TO ONE OF SAID CONNECTING RODS FOR RECIPROCATION WITH SAID RODS. 